TY - JOUR A1 - Blum, Carina A1 - Taskin, Mehmet Berat A1 - Shan, Junwen A1 - Schilling, Tatjana A1 - Schlegelmilch, Katrin A1 - Teßmar, Jörg A1 - Groll, Jürgen T1 - Appreciating the First Line of the Human Innate Immune Defense: A Strategy to Model and Alleviate the Neutrophil Elastase-Mediated Attack toward Bioactivated Biomaterials JF - Small N2 - Biointerface engineering is a wide-spread strategy to improve the healing process and subsequent tissue integration of biomaterials. Especially the integration of specific peptides is one promising strategy to promote the regenerative capacity of implants and 3D scaffolds. In vivo, these tailored interfaces are, however, first confronted with the innate immune response. Neutrophils are cells with pronounced proteolytic potential and the first recruited immune cells at the implant site; nonetheless, they have so far been underappreciated in the design of biomaterial interfaces. Herein, an in vitro approach is introduced to model and analyze the neutrophil interaction with bioactivated materials at the example of nano-bioinspired electrospun surfaces that reveals the vulnerability of a given biointerface design to the contact with neutrophils. A sacrificial, transient hydrogel coating that demonstrates optimal protection for peptide-modified surfaces and thus alleviates the immediate cleavage by neutrophil elastase is further introduced. KW - solution electrospinning KW - human neutrophil elastase (HNE) KW - peptide immobilization KW - polymeric matrix Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257691 VL - 17 IS - 13 ER - TY - JOUR A1 - Dogan, Leyla A1 - Scheuring, Ruben A1 - Wagner, Nicole A1 - Ueda, Yuichiro A1 - Schmidt, Sven A1 - Wörsdörfer, Philipp A1 - Groll, Jürgen A1 - Ergün, Süleyman T1 - Human iPSC-derived mesodermal progenitor cells preserve their vasculogenesis potential after extrusion and form hierarchically organized blood vessels JF - Biofabrication N2 - Post-fabrication formation of a proper vasculature remains an unresolved challenge in bioprinting. Established strategies focus on the supply of the fabricated structure with nutrients and oxygen and either rely on the mere formation of a channel system using fugitive inks or additionally use mature endothelial cells and/or peri-endothelial cells such as smooth muscle cells for the formation of blood vessels in vitro. Functional vessels, however, exhibit a hierarchical organization and multilayered wall structure that is important for their function. Human induced pluripotent stem cell-derived mesodermal progenitor cells (hiMPCs) have been shown to possess the capacity to form blood vessels in vitro, but have so far not been assessed for their applicability in bioprinting processes. Here, we demonstrate that hiMPCs, after formulation into an alginate/collagen type I bioink and subsequent extrusion, retain their ability to give rise to the formation of complex vessels that display a hierarchical network in a process that mimics the embryonic steps of vessel formation during vasculogenesis. Histological evaluations at different time points of extrusion revealed the initial formation of spheres, followed by lumen formation and further structural maturation as evidenced by building a multilayered vessel wall and a vascular network. These findings are supported by immunostainings for endothelial and peri-endothelial cell markers as well as electron microscopic analyses at the ultrastructural level. Moreover, endothelial cells in capillary-like vessel structures deposited a basement membrane-like matrix at the basal side between the vessel wall and the alginate-collagen matrix. After transplantation of the printed constructs into the chicken chorioallantoic membrane (CAM) the printed vessels connected to the CAM blood vessels and get perfused in vivo. These results evidence the applicability and great potential of hiMPCs for the bioprinting of vascular structures mimicking the basic morphogenetic steps of de novo vessel formation during embryogenesis. KW - vascular biofabrication KW - human iPSC-derived mesodermal cells (hiMPCs) KW - extrusion of hiMPC-containing bioinks alginate + collagen type I KW - multilayered vessel wall with intimate, media and adventitia KW - vascular network and hierarchical organized vessels KW - electron microscopy KW - serial block face EM Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254046 VL - 13 IS - 4 ER - TY - JOUR A1 - Doryab, Ali A1 - Taskin, Mehmet Berat A1 - Stahlhut, Philipp A1 - Schröppel, Andreas A1 - Orak, Sezer A1 - Voss, Carola A1 - Ahluwalia, Arti A1 - Rehberg, Markus A1 - Hilgendorff, Anne A1 - Stöger, Tobias A1 - Groll, Jürgen A1 - Schmid, Otmar T1 - A Bioinspired in vitro Lung Model to Study Particokinetics of Nano-/Microparticles Under Cyclic Stretch and Air-Liquid Interface Conditions JF - Frontiers in Bioengineering and Biotechnology N2 - Evolution has endowed the lung with exceptional design providing a large surface area for gas exchange area (ca. 100 m\(^{2}\)) in a relatively small tissue volume (ca. 6 L). This is possible due to a complex tissue architecture that has resulted in one of the most challenging organs to be recreated in the lab. The need for realistic and robust in vitro lung models becomes even more evident as causal therapies, especially for chronic respiratory diseases, are lacking. Here, we describe the Cyclic In VItro Cell-stretch (CIVIC) “breathing” lung bioreactor for pulmonary epithelial cells at the air-liquid interface (ALI) experiencing cyclic stretch while monitoring stretch-related parameters (amplitude, frequency, and membrane elastic modulus) under real-time conditions. The previously described biomimetic copolymeric BETA membrane (5 μm thick, bioactive, porous, and elastic) was attempted to be improved for even more biomimetic permeability, elasticity (elastic modulus and stretchability), and bioactivity by changing its chemical composition. This biphasic membrane supports both the initial formation of a tight monolayer of pulmonary epithelial cells (A549 and 16HBE14o\(^{-}\)) under submerged conditions and the subsequent cell-stretch experiments at the ALI without preconditioning of the membrane. The newly manufactured versions of the BETA membrane did not improve the characteristics of the previously determined optimum BETA membrane (9.35% PCL and 6.34% gelatin [w/v solvent]). Hence, the optimum BETA membrane was used to investigate quantitatively the role of physiologic cyclic mechanical stretch (10% linear stretch; 0.33 Hz: light exercise conditions) on size-dependent cellular uptake and transepithelial transport of nanoparticles (100 nm) and microparticles (1,000 nm) for alveolar epithelial cells (A549) under ALI conditions. Our results show that physiologic stretch enhances cellular uptake of 100 nm nanoparticles across the epithelial cell barrier, but the barrier becomes permeable for both nano- and micron-sized particles (100 and 1,000 nm). This suggests that currently used static in vitro assays may underestimate cellular uptake and transbarrier transport of nanoparticles in the lung. KW - lung cell model KW - cyclic stretch KW - ALI culture KW - bioinspired membrane KW - particle study Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223830 SN - 2296-4185 VL - 9 ER - TY - JOUR A1 - Doryab, Ali A1 - Taskin, Mehmet Berat A1 - Stahlhut, Philipp A1 - Schröppel, Andreas A1 - Wagner, Darcy E. A1 - Groll, Jürgen A1 - Schmid, Otmar T1 - A Biomimetic, Copolymeric Membrane for Cell‐Stretch Experiments with Pulmonary Epithelial Cells at the Air‐Liquid Interface JF - Advanced Functional Materials N2 - Chronic respiratory diseases are among the leading causes of death worldwide, but only symptomatic therapies are available for terminal illness. This in part reflects a lack of biomimetic in vitro models that can imitate the complex environment and physiology of the lung. Here, a copolymeric membrane consisting of poly(ε‐)caprolactone and gelatin with tunable properties, resembling the main characteristics of the alveolar basement membrane is introduced. The thin bioinspired membrane (≤5 μm) is stretchable (up to 25% linear strain) with appropriate surface wettability and porosity for culturing lung epithelial cells under air–liquid interface conditions. The unique biphasic concept of this membrane provides optimum characteristics for initial cell growth (phase I) and then switch to biomimetic properties for cyclic cell‐stretch experiments (phase II). It is showed that physiologic cyclic mechanical stretch improves formation of F‐actin cytoskeleton filaments and tight junctions while non‐physiologic over‐stretch induces cell apoptosis, activates inflammatory response (IL‐8), and impairs epithelial barrier integrity. It is also demonstrated that cyclic physiologic stretch can enhance the cellular uptake of nanoparticles. Since this membrane offers considerable advantages over currently used membranes, it may lead the way to more biomimetic in vitro models of the lung for translation of in vitro response studies into clinical outcome. KW - alveolar‐capillary barrier KW - cyclic mechanical stretch KW - hybrid polymers KW - in vitro cell‐stretch model KW - tunable ultra‐thin biphasic membrane Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225645 VL - 31 IS - 10 ER - TY - JOUR A1 - Garitano-Trojaola, Andoni A1 - Sancho, Ana A1 - Götz, Ralph A1 - Eiring, Patrick A1 - Walz, Susanne A1 - Jetani, Hardikkumar A1 - Gil-Pulido, Jesus A1 - Da Via, Matteo Claudio A1 - Teufel, Eva A1 - Rhodes, Nadine A1 - Haertle, Larissa A1 - Arellano-Viera, Estibaliz A1 - Tibes, Raoul A1 - Rosenwald, Andreas A1 - Rasche, Leo A1 - Hudecek, Michael A1 - Sauer, Markus A1 - Groll, Jürgen A1 - Einsele, Hermann A1 - Kraus, Sabrina A1 - Kortüm, Martin K. T1 - Actin cytoskeleton deregulation confers midostaurin resistance in FLT3-mutant acute myeloid leukemia JF - Communications Biology N2 - The presence of FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is one of the most frequent mutations in acute myeloid leukemia (AML) and is associated with an unfavorable prognosis. FLT3 inhibitors, such as midostaurin, are used clinically but fail to entirely eradicate FLT3-ITD+AML. This study introduces a new perspective and highlights the impact of RAC1-dependent actin cytoskeleton remodeling on resistance to midostaurin in AML. RAC1 hyperactivation leads resistance via hyperphosphorylation of the positive regulator of actin polymerization N-WASP and antiapoptotic BCL-2. RAC1/N-WASP, through ARP2/3 complex activation, increases the number of actin filaments, cell stiffness and adhesion forces to mesenchymal stromal cells (MSCs) being identified as a biomarker of resistance. Midostaurin resistance can be overcome by a combination of midostaruin, the BCL-2 inhibitor venetoclax and the RAC1 inhibitor Eht1864 in midostaurin-resistant AML cell lines and primary samples, providing the first evidence of a potential new treatment approach to eradicate FLT3-ITD+AML. Garitano-Trojaola et al. used a combination of human acute myeloid leukemia (AML) cell lines and primary samples to show that RAC1-dependent actin cytoskeleton remodeling through BCL2 family plays a key role in resistance to the FLT3 inhibitor, Midostaurin in AML. They showed that by targeting RAC1 and BCL2, Midostaurin resistance was diminished, which potentially paves the way for an innovate treatment approach for FLT3 mutant AML. KW - actin KW - acute myeloid leukaemia Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260709 VL - 4 IS - 1 ER - TY - JOUR A1 - Götz, Lisa-Marie A1 - Holeczek, Katharina A1 - Groll, Jürgen A1 - Jüngst, Tomasz A1 - Gbureck, Uwe T1 - Extrusion-Based 3D Printing of Calcium Magnesium Phosphate Cement Pastes for Degradable Bone Implants JF - Materials N2 - This study aimed to develop printable calcium magnesium phosphate pastes that harden by immersion in ammonium phosphate solution post-printing. Besides the main mineral compound, biocompatible ceramic, magnesium oxide and hydroxypropylmethylcellulose (HPMC) were the crucial components. Two pastes with different powder to liquid ratios of 1.35 g/mL and 1.93 g/mL were characterized regarding their rheological properties. Here, ageing over the course of 24 h showed an increase in viscosity and extrusion force, which was attributed to structural changes in HPMC as well as the formation of magnesium hydroxide by hydration of MgO. The pastes enabled printing of porous scaffolds with good dimensional stability and enabled a setting reaction to struvite when immersed in ammonium phosphate solution. Mechanical performance under compression was approx. 8–20 MPa as a monolithic structure and 1.6–3.0 MPa for printed macroporous scaffolds, depending on parameters such as powder to liquid ratio, ageing time, strand thickness and distance. KW - magnesium phosphate cement KW - extrusion-based 3D printing KW - degradable implant Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246110 SN - 1996-1944 VL - 14 IS - 18 ER - TY - JOUR A1 - Haider, Malik Salman A1 - Ahmad, Taufiq A1 - Groll, Jürgen A1 - Scherf-Clavel, Oliver A1 - Kroiss, Matthias A1 - Luxenhofer, Robert T1 - The Challenging Pharmacokinetics of Mitotane: An Old Drug in Need of New Packaging JF - European Journal of Drug Metabolism and Pharmacokinetics N2 - Adrenocortical carcinoma (ACC) is a malignant tumor originating from the adrenal gland cortex with a heterogeneous but overall dismal prognosis in advanced stages. For more than 50 years, mitotane has remained a cornerstone for the treatment of ACC as adjuvant and palliative therapy. It has a very poor aqueous solubility of 0.1 mg/l and high partition coefficient in octanol/water (log P) value of 6. The commercially available dosage form is 500 mg tablets (Lysodren®). Even at doses up to 6 g/day (12 tablets in divided doses) for several months, > 50% patients do not achieve therapeutic plasma concentration > 14 mg/l due to poor water solubility, large volume of distribution and inter/intra-individual variability in bioavailability. This article aims to give a concise update of the clinical challenges associated with the administration of high-dose mitotane oral therapy which encompass the issues of poor bioavailability, difficult-to-predict pharmacokinetics and associated adverse events. Moreover, we present recent efforts to improve mitotane formulations. Their success has been limited, and we therefore propose an injectable mitotane formulation instead of oral administration, which could bypass many of the main issues associated with high-dose oral mitotane therapy. A parenteral administration of mitotane could not only help to alleviate the adverse effects but also circumvent the variable oral absorption, give better control over therapeutic plasma mitotane concentration and potentially shorten the time to achieve therapeutic drug plasma concentrations considerably. Mitotane as tablet form is currently the standard treatment for adrenocortical carcinoma. It has been used for 5 decades but suffers from highly variable responses in patients, subsequent adverse effects and overall lower response rate. This can be fundamentally linked to the exceedingly poor water solubility of mitotane itself. In terms of enhancing water solubility, a few research groups have attempted to develop better formulations of mitotane to overcome the issues associated with tablet dosage form. However, the success rate was limited, and these formulations did not make it into the clinics. In this article, we have comprehensively reviewed the properties of these formulations and discuss the reasons for their limited utility. Furthermore, we discuss a recently developed mitotane nanoformulation that led us to propose a novel approach to mitotane therapy, where intravenous delivery supplements the standard oral administration. With this article, we combine the current state of knowledge as a single piece of information about the various problems associated with the use of mitotane tablets, and herein we postulate the development of a new injectable mitotane formulation, which can potentially circumvent the major problems associated to mitotane's poor water solubility. KW - Mitotane KW - cancer KW - adrenal gland Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270476 SN - 2107-0180 VL - 46 IS - 5 ER - TY - JOUR A1 - Haider, Malik Salman A1 - Ahmad, Taufiq A1 - Yang, Mengshi A1 - Hu, Chen A1 - Hahn, Lukas A1 - Stahlhut, Philipp A1 - Groll, Jürgen A1 - Luxenhofer, Robert T1 - Tuning the thermogelation and rheology of poly(2-oxazoline)/poly(2-oxazine)s based thermosensitive hydrogels for 3D bioprinting JF - Gels N2 - As one kind of “smart” material, thermogelling polymers find applications in biofabrication, drug delivery and regenerative medicine. In this work, we report a thermosensitive poly(2-oxazoline)/poly(2-oxazine) based diblock copolymer comprising thermosensitive/moderately hydrophobic poly(2-N-propyl-2-oxazine) (pPrOzi) and thermosensitive/moderately hydrophilic poly(2-ethyl-2-oxazoline) (pEtOx). Hydrogels were only formed when block length exceeded certain length (≈100 repeat units). The tube inversion and rheological tests showed that the material has then a reversible sol-gel transition above 25 wt.% concentration. Rheological tests further revealed a gel strength around 3 kPa, high shear thinning property and rapid shear recovery after stress, which are highly desirable properties for extrusion based three-dimensional (3D) (bio) printing. Attributed to the rheology profile, well resolved printability and high stackability (with added laponite) was also possible. (Cryo) scanning electron microscopy exhibited a highly porous, interconnected, 3D network. The sol-state at lower temperatures (in ice bath) facilitated the homogeneous distribution of (fluorescently labelled) human adipose derived stem cells (hADSCs) in the hydrogel matrix. Post-printing live/dead assays revealed that the hADSCs encapsulated within the hydrogel remained viable (≈97%). This thermoreversible and (bio) printable hydrogel demonstrated promising properties for use in tissue engineering applications. KW - poly(2-ethyl-2-oxazoline) KW - shear thinning KW - shape fidelity KW - cyto-compatibility KW - bio-printability Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241781 SN - 2310-2861 VL - 7 IS - 3 ER - TY - JOUR A1 - Holzmeister, Ib A1 - Weichhold, Jan A1 - Groll, Jürgen A1 - Zreiqat,, Hala A1 - Gbureck, Uwe T1 - Hydraulic reactivity and cement formation of baghdadite JF - Journal of the American Ceramic Society N2 - In this study, the hydraulic reactivity and cement formation of baghdadite (Ca\(_{3}\)ZrSi\(_{2}\)O\(_{9}\)) was investigated. The material was synthesized by sintering a mixture of CaCO\(_{3}\), SiO\(_{2}\), and ZrO\(_{2}\) and then mechanically activated using a planetary mill. This leads to a decrease in particle and crystallite size and a partial amorphization of baghdadite as shown by X-ray powder diffraction (XRD) and laser diffraction measurements. Baghdadite cements were formed by the addition of water at a powder to liquid ratio of 2.0 g/ml. Maximum compressive strengths were found to be ~2 MPa after 3-day setting for a 24-h ground material. Inductively coupled plasma mass spectrometry (ICP-MS) measurements showed an incongruent dissolution profile of set cements with a preferred dissolution of calcium and only marginal release of zirconium ions. Cement formation occurs under alkaline conditions, whereas the unground raw powder leads to a pH of 11.9 during setting, while prolonged grinding increased pH values to approximately 12.3. KW - baghdadite KW - bone cement KW - hydraulic reactivity KW - mechanical activation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259457 VL - 104 IS - 7 ER - TY - JOUR A1 - Horder, Hannes A1 - Guaza Lasheras, Mar A1 - Grummel, Nadine A1 - Nadernezhad, Ali A1 - Herbig, Johannes A1 - Ergün, Süleyman A1 - Teßmar, Jörg A1 - Groll, Jürgen A1 - Fabry, Ben A1 - Bauer-Kreisel, Petra A1 - Blunk, Torsten T1 - Bioprinting and differentiation of adipose-derived stromal cell spheroids for a 3D breast cancer-adipose tissue model JF - Cells N2 - Biofabrication, including printing technologies, has emerged as a powerful approach to the design of disease models, such as in cancer research. In breast cancer, adipose tissue has been acknowledged as an important part of the tumor microenvironment favoring tumor progression. Therefore, in this study, a 3D-printed breast cancer model for facilitating investigations into cancer cell-adipocyte interaction was developed. First, we focused on the printability of human adipose-derived stromal cell (ASC) spheroids in an extrusion-based bioprinting setup and the adipogenic differentiation within printed spheroids into adipose microtissues. The printing process was optimized in terms of spheroid viability and homogeneous spheroid distribution in a hyaluronic acid-based bioink. Adipogenic differentiation after printing was demonstrated by lipid accumulation, expression of adipogenic marker genes, and an adipogenic ECM profile. Subsequently, a breast cancer cell (MDA-MB-231) compartment was printed onto the adipose tissue constructs. After nine days of co-culture, we observed a cancer cell-induced reduction of the lipid content and a remodeling of the ECM within the adipose tissues, with increased fibronectin, collagen I and collagen VI expression. Together, our data demonstrate that 3D-printed breast cancer-adipose tissue models can recapitulate important aspects of the complex cell–cell and cell–matrix interplay within the tumor-stroma microenvironment KW - adipose-derived stromal cells KW - adipose tissue KW - bioprinting KW - breast cancer model KW - extracellular matrix KW - hyaluronic acid KW - spheroids Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236496 VL - 10 IS - 4 ER -